I agree that a warning about SaaSS should be included if it's present
(actually I think such applications shouldn't be included in f-droid in the
first place).
However, a messaging software is not what you call SaaSS, since you can't do
the job with your own computer.
It's just the same thing like using this forum:
I use a free software program (my browser) in order to send and receive text
to a server. What kind of software on the server is running doesn't matter,
since gave somebody else control over my data anyway.
Though I agree that hosting your own jabber server is a better option.
